UV Vertex using Python?
You access the UV coords by looping over face loops.

import bpy
import bmesh

#retrieve mesh in object mode
if bpy.context.active_object.mode!='OBJECT'
    bpy.ops.object.mode_set(mode='OBJECT')
mesh = bpy.context.object.data
bm = bmesh.new()
bm.from_mesh(mesh)
uv_layer = bm.loops.layers.uv.active

for face in bm.faces:
    for vert in face.loops:
        # here are the UV coords
        print(vert[uv_layer].uv)

#write the mesh back if you changed the uvs
bm.to_mesh(mesh)